Logging in whenever you want to browse the forum is safer with your passwords saved in your head and not any of your device or browser, especially for people that` use public or general browsers and wifi networks; but if you will be using the forum regularly, then there is need to save your password if you are the only person accessing your browser, and no one is having access to your phone, but if you share your phone with others, then there is a need for you to create a unique password, and if possible, you should be using a secrate tab for browsing the forum to be completely safe.
Use your forum account regularly, daily will have less reason to save your password, because if you type your password daily, you will not forget it. Your advice is opposite to what people need to do.
In addition, using your brain and memory to remember your account password is not my advice and generally no security expert will recommend this method. Use password managers to create strong passwords and back it up too.
[GUIDE] How to Create a Strong/Secure PasswordSecurity and Privacy EncylopediaAre your passwords in the green?